Washington, DC Tap Water Quality Report (2026): Lead, PFAS, Disinfection & Hardness
DC Water (District of Columbia Water and Sewer Authority)
Which filter fits DC water?
Under-sink reverse osmosis
The strongest kitchen-tap option if your home has a lead service line, galvanized pipe or old lead solder. EPA puts RO systems at about $150–$1,000 before cartridges and says to look for NSF/ANSI 58, or NSF/ANSI 53 for PFAS reduction (EPA filter guide). Check the maker’s listing for a lead claim.
See Waterdrop G3P800 → See APEC RO →FTC disclosure: product buttons are affiliate links; we may earn a commission at no extra cost to you. Grades come only from public DC Water/EPA/USGS data. Disclosure.
Countertop reverse osmosis
No under-sink install. Check the maker’s certification listing for lead and PFAS before you buy (EPA filter guide).
See AquaTru Countertop →FTC disclosure: product buttons are affiliate links; we may earn a commission at no extra cost to you. Grades come only from public DC Water/EPA/USGS data. Disclosure.
Whole-house filtration
DC water is disinfected with chloramine most of the year and with chlorine for a short time each spring (DC Water 2026 Drinking Water Quality Report (2025 data)). A whole-house carbon system is a taste and odor choice; check that the model is rated for chloramine. It does not soften hard water, and it is not a substitute for replacing a lead service line.
See SpringWell Whole-House → See Aquasana Rhino →FTC disclosure: product buttons are affiliate links; we may earn a commission at no extra cost to you. Grades come only from public DC Water/EPA/USGS data. Disclosure.
DC decision table
| Option | Best for (and what to check) | Cost | Next step |
|---|---|---|---|
| Tap water as-is | Homes with no lead or galvanized service line (check the DC Water service line map; order a free DC Water lead test) | $0 | Check your ZIP |
| Carbon filter | Chlorine taste (NSF/ANSI 53 listing for lead or PFAS claims) | $20–$1,000 (EPA) | See Aquasana → |
| Countertop RO | Renters (certification listing; cartridge cost) | See maker | See AquaTru → |
| Under-sink RO | Most lead and PFAS margin at the tap (NSF/ANSI 58 listing; membrane cost) | $150–$1,000 (EPA) | See Waterdrop → |
| Whole-house carbon | Chlorine and chloramine taste at every tap (does not soften hard water) | Get a quote | See SpringWell → |
FTC disclosure: product buttons are affiliate links; we may earn a commission at no extra cost to you. Grades come only from public DC Water/EPA/USGS data. Disclosure.
How we graded Washington, DC (transparent rubric)
Every deduction below comes from a public number with its source.
| Factor | Points |
|---|---|
| Start | 100 |
| PFOA highest 2.4 ppt and PFOS highest 3.1 ppt in 2025 Washington Aqueduct monitoring, both at or below EPA’s 4.0 ppt limits | 0 |
| Other PFAS detected (PFBS, PFBA, PFPeA and PFHxA in 2025; PFPeA and PFHxA in EPA UCMR 5, July 2024) | −3 |
| Lead detected at some taps (90th percentile 1 and 2 ppb; 2 of 105 and 2 of 106 homes over the 15 ppb action level, 2025; goal is zero) | −3 |
| TTHM: highest locational running annual average 50 ppb, single-site results 17–73 ppb, vs 80 ppb limit | 0 |
| Lithium not detected in any UCMR 5 sample (reporting level 9 ppb, 2024) | 0 |
| Hardness: 139 mg/L average (about 8 gpg); hard on the USGS scale | −6 |
| Score | 88 = B+ |
Deduction rules (same as our Columbus, Fort Worth and Seattle reports): any PFOA or PFOS result above 4.0 ppt −5; other PFAS detected −3; lithium above EPA’s 10 ppb health reference level −3; lead detected at the tap −3; TTHM above 80 ppb at any location −10; hardness moderately hard −4, hard −6, very hard −8. Scale: 93+ A, 90–92 A−, 87–89 B+, 83–86 B, 80–82 B−, 77–79 C+, 73–76 C, 70–72 C−, 67–69 D+, 63–66 D, 60–62 D−, below 60 F.
Sources: DC Water 2026 Drinking Water Quality Report (2025 data); EPA UCMR 5 data (PWSID DC0000002, 2024 sampling); USGS hardness scale; all accessed Nov 1, 2026.
DC water, explained in plain English
The risk is in service lines and plumbing
DC Water says lead service lines and lead solder used on copper pipes before 1987 are the main sources of lead, and galvanized pipe downstream of lead can also release it. The 90th percentile was 1–2 ppb in 2025, but single results reached 243 ppb, so check your own line (DC Water 2026 Drinking Water Quality Report (2025 data)).
Detected, below EPA limits
EPA’s enforceable limits are 4.0 ppt each for PFOA and PFOS (EPA PFAS rule). In 2025, PFOA averaged 0.5 ppt and PFOS 1.1 ppt at the Aqueduct’s plants; PFHxS, PFNA and GenX were not detected (DC Water 2026 Drinking Water Quality Report (2025 data)).
TTHM under limits, hard water
The highest running averages were 50 ppb for total trihalomethanes and 34 ppb for haloacetic acids, under limits of 80 and 60 ppb (DC Water 2026 Drinking Water Quality Report (2025 data)). Hardness averaged 139 mg/L; USGS calls 121–180 mg/L hard (DC Water 2026 Drinking Water Quality Report (2025 data), USGS).
Free 6-Month Replacement Filter Reminder
Filter makers set replacement intervals for each cartridge, and an overdue cartridge stops doing its job. Pick your system and we will remind you at 6 months to check your maker's schedule.
What Does Filtered Water Cost in Washington, DC?
- Ongoing cost never ends
- Use your store's real price below
- Look for NSF/ANSI 53 for lead
- Good for chlorine taste
- Look for NSF/ANSI 58
- Point-of-use: kitchen tap only
5-year cost calculator (starting values are examples only; enter your own)
Filter 5-yr cost = system price + (cartridge price × changes per year × 5). Bottled 5-yr cost = price per gallon × gallons per day × 365 × 5.
FTC disclosure: product buttons are affiliate links; we may earn a commission at no extra cost to you. Grades come only from public DC Water/EPA/USGS data. Disclosure.
Washington, DC tap water checklist
- Look up your ZIP. Enter your ZIP in the CleanWaterGrade lookup. EPA UCMR 5 records list DC Water as serving ZIP codes across the District, from 20001 to 20599.
- Check your service line. Use DC Water's service line map at dcwater.com/servicemap, and check the pipe where water enters your home. DC Water says lead is dull silver-gray, scratches easily with a coin, and a strong magnet won't stick to it.
- Order a free lead test. DC Water provides free lead test kits to homes and businesses; call 202-612-3440 or email [email protected].
- Flush before drinking. If you have or may have lead pipes, run cold water until the temperature changes, then let it run two more minutes. Use only cold water for drinking, cooking and infant formula, and clean faucet aerators every 3 months.
- Pick a certified filter. DC Water says a lead filter should be certified to NSF/ANSI 53 for lead reduction and NSF/ANSI 42 for particle reduction. For PFAS, EPA says look for NSF/ANSI 53 or 58.
- Set a cartridge reminder. Filters only work when cartridges are changed on schedule. Replace cartridges on the maker's schedule; use the free 6-month reminder below.
Run the ZIP lookup → Related: Baltimore, Philadelphia, New York, Columbus, EPA PFAS limits explained, best RO systems, water hardness by ZIP, whole-house filter vs RO.
Other DC results worth knowing
- The Washington Aqueduct draws about 140 million gallons a day from the Potomac River at Great Falls and Little Falls (DC Water 2026 Drinking Water Quality Report (2025 data)).
- Treated-water turbidity peaked at 0.08 NTU, and 100% of monthly readings were at or below 0.3 NTU (DC Water 2026 Drinking Water Quality Report (2025 data)).
- Fluoride is added to 0.7 ppm; nitrate peaked at 2 ppm (limit 10), arsenic at 0.3 ppb (limit 10) and atrazine at 0.2 ppb (limit 3) (DC Water 2026 Drinking Water Quality Report (2025 data)).
- Sodium averaged 32 ppm (range 22–47) (DC Water 2026 Drinking Water Quality Report (2025 data)).
- Total coliform bacteria peaked at 1.2% of monthly samples (11 of 3,011 samples for the year), against a 5% trigger, with no violation (DC Water 2026 Drinking Water Quality Report (2025 data)).
- Copper at the tap: 90th percentile 0.098 and 0.084 ppm, with no homes over the 1.3 ppm action level (DC Water 2026 Drinking Water Quality Report (2025 data)).
- DC Water says its tap water costs $0.02 per gallon, versus an average of $1.23 per gallon for bottled water (DC Water 2026 Drinking Water Quality Report (2025 data)).
- EPA’s 2024 rule also set limits for PFHxS, PFNA, GenX and a Hazard Index. EPA has since proposed keeping the 4.0 ppt PFOA/PFOS limits with an option to request until 2031 to comply, and rescinding the PFHxS, PFNA, GenX and Hazard Index limits (EPA PFAS rule).
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FAQs
Is Washington, DC tap water safe to drink?
DC Water says its water complied with all EPA drinking water standards in 2025. The 90th-percentile lead result was 1 ppb in the January-June round and 2 ppb in July-December, with 2 of 105 and 2 of 106 homes over the 15 ppb action level. The highest locational running annual average for total trihalomethanes was 50 ppb, under the 80 ppb limit, and PFOA and PFOS stayed below EPA's 4.0 ppt limits.
Does DC tap water have PFAS?
Low levels, below EPA's limits. In 2025 voluntary monitoring at the Washington Aqueduct's two treatment plants, PFOA averaged 0.5 ppt (highest 2.4) and PFOS averaged 1.1 ppt (highest 3.1), against EPA limits of 4.0 ppt each. PFHxS, PFNA and GenX were not detected, while PFBS, PFBA, PFPeA and PFHxA were found at a few parts per trillion. EPA UCMR 5 testing in 2024 found PFPeA and PFHxA in July samples and no lithium.
Is there lead in DC's water?
The main risk is lead pipes and plumbing, not the water leaving the plant. DC Water says lead service lines were mostly installed before the mid-1950s, with records of some as late as 1977, and lead solder was used on copper pipes before 1987. In 2025 tap sampling, the highest single lead result was 243 ppb, even though the 90th percentile was 1 to 2 ppb. DC Water offers a service line map, free lead test kits and replacement programs, most offering free replacements.
Is DC water hard or soft?
Hard. DC Water reports total hardness averaging 139 mg/L, or about 8 grains per gallon, with a range of 84 to 194 mg/L (5 to 11 gpg) in 2025. USGS calls 121 to 180 mg/L hard. Hardness affects scale and soap, not health.
Why does DC tap water smell like chlorine in the spring?
Most of the year the Washington Aqueduct uses chloramine to keep water disinfected in the pipes. For a short time each spring it switches to chlorine only, which DC Water says is standard practice and safe to drink. To reduce the taste, DC Water suggests keeping an open pitcher of water in the fridge.
Sources (all accessed Nov 1, 2026)
- DC Water 2026 Drinking Water Quality Report (2025 data) (2025 data, including 2025 lead and copper sampling and PFAS monitoring)
- DC Water service line map
- EPA UCMR 5 data (UCMR5 by-state file and UCMR5_ZIPCodes.txt; PWSID DC0000002)
- EPA SDWIS record (D.C. Water and Sewer Authority, population served)
- EPA PFAS rule
- EPA filter guide
- USGS, Hardness of water